He gets animalistic in action flick The Legend of Tarzan, but actor Alexander Skarsgard says his only injuries were sustained during a sex scene with co-star Margot Robbie

Best known to audiences as sexy vampire Eric Northman on the HBO TV series True Blood, which ended its run in 2014, actor Alexander Skarsgard is now heating up the big screen with his big break, The Legend Of Tarzan.

The 39-year-old plays the title role of John Clayton aka Lord Greystoke, the man known as Tarzan, who was reared by apes and is now in England taking his place in the House of Lords, with his wife Jane (Margot Robbie) by his side.

When he is sent back to the Congo to serve as a trade emissary of Parliament, he is unaware that he is a pawn in a deadly game orchestrated by the King of Belgium's envoy (Christoph Waltz).

The action adventure flick opens here tomorrow.

Skarsgard is poised to make female fans swoon even more because of a sex scene during which, surprisingly, Skarsgard sustained the only "injuries" on the shoot. They came courtesy of his co-star Robbie.

At our interview at the Beverly Hilton hotel in Beverly Hills, he said of his bruises: "(Director) David Yates was, like, 'it needs to be animalistic. We need to feel the intensity. Come on, it's Tarzan and Jane having sex. It can't be like a missionary position'."

The strapping 1.93m-tall hunk's Tarzan muscles are still visible even though he said he has given up the intense training and diet.

Of his punishing regimen, he said: "I wanted to put on weight in the beginning, so for the first three months, I was on a 7,000 calorie a day diet, which meant that I basically walked around on the True Blood set with Tupperware with steak and potatoes, just eating constantly.

"I lifted weights so I put on weight, but the goal wasn't just to get bigger. I didn't want Tarzan to look like a bodybuilder in the jungle.

"When he moves through the jungle, he has to be very athletic and flexible and nimble."

The second phase was when he arrived in England for the shoot at the old Harry Potter studios at Leavesden, outside London.

"I started working with a choreographer on movement. It was yoga, Pilates, that kind of stuff, to get more athletic."

He had to buy a whole new wardrobe to accommodate the new body, "but I also didn't have a social life for nine months, so it wasn't like I needed a lot of clothes... I couldn't drink and I was on a very strict diet".

Skarsgard followed in the footsteps of his father Stellan, an actor and now 65. After a brief stint in the Swedish military, Skarsgard was in various indie movies like Straw Dogs, Melancholia and Disconnect as well as the war-themed TV mini-series Generation Kill.

So his first leading role in a US$180 million tentpole blockbuster was incredibly exciting for him.

"The set looked like an amusement park. It was the biggest movie set I've seen in my life and I couldn't believe it when I saw that I got to play there all day and that was my job for the next six months," he said.

HUGE SET

Leavesden is an old Rolls-Royce airplane factory and a year before shooting started, film studio Warner Bros. turned two of the hangars into jungle sets 274m long. There were massive trees and real bushes, and African grass was planted to recreate a savannah and an artificial lake.

A second unit went to Gabon to shoot backgrounds so that the vistas looked authentic.

CGI features prominently in the film as Tarzan has to interact with his brother apes and other wild animals.

No real animals were used in the shoot - all were lovingly recreated using cutting-edge visual effects.

There is a scene where Skarsgard fights his ape brother Akut - "a stuntman in a sumo wrestling suit, basically".

In a scene with a majestic lion, Tarzan nuzzles him in greeting.

"(That) was also a stunt guy in pyjamas, which was slightly awkward to shoot because we met five minutes before. He was, like, 'Hey, what's up dude, and then down on all fours'."

Skarsgard added "The scene with the elephant was a tennis ball on a C-Stand so that really felt like Day One of drama school in a way, where I had to have this emotional connection with this tennis ball.

"So it was quite exciting for me to watch the movie two months ago and to see how this tennis ball transformed into this beautiful elephant and how the stuntman in his grey pyjamas was suddenly like this beautiful lion."

Skarsgard attributes his love for Tarzan to his dad, who worshipped the character as a kid.

"Every Saturday, they would play these old Johnny Weissmuller movies in Stockholm at the local movie theatre and he would save up his money and go see them.

"When he had a son, he wanted to introduce (me) to his biggest idol, so I fell in love with Tarzan and the jungle through my father watching these old movies together."

And it will be a family affair at the Stockholm premiere of The Legend Of Tarzan in two weeks' time, with his sister hosting the after-party.

Skarsgard says: "My dad was more excited than I was when I got the job... Out of all these premieres around the world, that's the one I'm most excited about.

"To watch this movie next to my dad who introduced me to the character is going to be a pretty cool experience."

David (Yates) wanted to feel like she's really into it and it gets primal, so he was just egging her on (from) behind the camera going, like, 'Beat him, scratch him, hit him'.

- Alexander Skarsgard (above) on his co-star Margot Robbie during their sex scene

Margot Robbie's Jane is no shrinking violet

Australian actress Margot Robbie burst on the international scene with Martin Scorsese's The Wolf Of Wall Street (2013), where she played Leonardo DiCaprio's sexy wife.

Before that, the cheerful 25-year-old's resume in Hollywood was slender, though she starred in the long-running Australian TV series Neighbours for a few years.

But her star has been on the rise, with roles in last year's Focus opposite Will Smith and as supervillain Harley Quinn in the upcoming Suicide Squad.

And, of course, the project we are at the Beverly Hilton to talk about, The Legend Of Tarzan, where she plays Jane, who is no shrinking violet or damsel in distress.

When kidnapped by the baddie (Christoph Waltz) as bait for Tarzan's capture, she more than holds her own, gamely throwing herself into rivers, rescuing allies and fighting alongside her husband.

And thankfully, the blonde bombshell is not in the obligatory skimpy jungle outfits.

How would you describe your version of Jane?

It's set in the late 1800s. She seems like a bit of a rebel for that time. She doesn't want to conform to Victorian London. She grew up in the Congo. She seems a bit defiant and when she said, 'I want to go to Africa too' and John is, like, 'No we're not', she's, like, 'Well, we are'. And he's, like, 'Okay, fine we're going'. So I liked that. She's just a little bit defiant and bossy.

How was it working with Alexander Skarsgard?

As an actor, I so admire the choices he makes. And he gives such varied performances.

You watch something like The Diary Of A Teenage Girl and then you watch something like The Legend Of Tarzan - you can hardly believe it's the same person.

I think he takes on roles that a lot of leading (men) wouldn't and I admire him for that.

As a person, he is just the loveliest human being. I think it's a testament to how he's brought up. He's really raised well. He's just a very respectful, charming, lovely person.

And how about that sex scene?

I think it was an opportunity to explore their relationship in a different way. When you're watching Tarzan and Jane, two people who have such primal urges evidently and are so madly in love, you want that to be represented in their love life.

RISING STAR: Australian actress Margot Robbie is no damsel in distress in her latest leading role as Tarzan's wife Jane.

And I was, like, 'Okay, we're going for it, sure'. So, yeah, it was fun.

NB. At our interview at the Beverly Hilton hotel in Beverly Hills, Skarsgard said of his bruises: "(Director) David Yates was, like, 'it needs to be animalistic. We need to feel the intensity. Come on, it's Tarzan and Jane having sex. It can't be like a missionary position'."

"David wanted to feel like she's really into it and it gets primal, so he was just egging her on (from) behind the camera, going, like, 'Beat him, scratch him, hit him'.